Mold jacket



Dec. 24, 1940. 1 F HINES MOLD JACKET FiledAug. 24, 193B ATToRNEmy,

Patented Dec. Z4, 1940 UNITED STATES PATENT OFFICE MOLD JACKET Application August 24, 1938, Serial No. 226,498

1 Claim.

This invention relates to foundry jackets and asks in which it is vitally necessary that all of a large number of such implements be precisely interchangeable, with a limit of tolerance on the order of a few thousandths of an inch, so that any jacket of a given size will t upon a sand mold of corresponding size closely and accurately, thereby insuring a perfect casting when the mold is poured.

The present application is a continuation in part of my co-pending application Serial No. 148,492, led June 16, 1937, now Pat. 2,154,749.

This present jacket is made of sides cut from sheet stock and connected together solely by cast metal corners. In the present application an improved cast corner is also included, characterized by more secure anchorage than previously between the corner and its two adjoining sides, and also by minimizing shrinkage of the corner casting and thus any tendency due to warping caused by such shrinkage is eliminated.

In the formation of foundry flasks and jackets, lightness of weight and accuracy of size are highly important, the former to reduce fatigue to the workman.

Accuracy of size is essential for the reason that the usual foundry practice is to make sand molds in large quantities from a single flask or a few asks, remove them from the flask and set them out on the floor for pouring. In order to keep the pouring pressure from bursting the mold, it is necessary to put a jacket on the mold While pouring. Although jacketing is sometimes done by such crude means as inaccurately formed iron bands or wooden jackets, such are unsatisfactory for use in the production of castings to close finish specifications with a minimum of subsequent machining. For accurate work, the sides of the jacket must fit upon the sides of the sand mold in the precise relation that was occupied initially by the walls of the forming ask. Failure of such exact correspondence will permit some yielding of the sand with corresponding discrepancies or inaccuracies of the finished casting. Even for rough castings crudely made jackets cause production losses due to failure of the jacket to sustain all parts of the sand against lateral pres sure. A further difiiculty with wood jackets is that when the mold breaks, permitting metal to ow through and against the wall, the molten metal burns the wood and destroys the jacket.

Objection to iron and aluminum flasks and jackets are Weight in the case of iron, and expense in the case of aluminum. To avoid both, the amount of metal is reduced, making a thinwalled mold container, likely to be broken or get holes punched in the walls, and with aluminum the walls may be burned through by iron spilled on them.

Little or no effort has hitherto been devoted to the use in flask jacket manufacture of composition materials of the synthetic board variety. largely because of the difficulties of making a permanently accurate fit and a solid joint that will not weave, an inherent disadvantage which such material shares with wood. To obtain and maintain proper t it has hitherto been necessary to use such boards in the form of panel inserts in metal frames. One of the present purposes is to make a durable accurate jacket of such material, with metal only at the corners.

To the accomplishment of the foregoing and related ends, said invention, then, consists of the structure and means hereinafter fully described and particularly pointed out in the claim.

The annexed drawing and the following description set forth in detail certain structure embodying the invention, such disclosed means constituting, however, but one of various structural forms in which the principle of the invention may be used.

In the accompanying drawing:

Fig. 1 is a perspective of a jacket embodying my present invention;

Fig. 2 is a perspective showing a corner only of a modified form;

Fig. 3 is a corner detail in horizontal section on the plane 3-3 of Fig. 1;

Fig. 4 is a corner detail in horizontal section on the plane 4-4 of Fig. 1, and

Fig. 5 is an inner face elevation of the end of a panel prepared for assembly.

Referring now to Fig. 1, my improved mold container, in the embodiment there illustrated, comprises side walls I, I and end walls 2, 2, mutually connected by cast corners 3. For convenience handles such as 4 may be fastened to the ends. The side walls and end walls consist of panels of material, preferably synthetic board, Transite, for example, cut to proper s-ize. One end of such a panel is shown in Fig. 5 and is there illustrated as grooved on opposite sides, as at I and I2, near and generally parallel to the upright end. There is a series of holes I3 through from inner groove I0 flared to the outer face, and a similar series of holes I4 from the outer groove I2 to the inner face. These grooves serve for engagement with the cast metal of the corners 3 as is particularly illustrated in Figs. 3 and 4. Such grooves and flared holesy are the preferred form for engagement of the metal of the corner with the panel material.

The corners 3 are formed of cast aluminum or other metal, surrounding and engaging upon and through the ends of the wall panels, and preferably formed by apparatus and methods similar to the disclosure in my co-pending application Serial No. 148,492.

In orderl to reduce the amount of metal in the corners which is subject to shrinkage, the outside of the corner castings 3 are grooved as at 20, thus conning the metal only to the amount needed to. cover the terminal edges of the panels I and 2.

Connecting webs 2| may bridge the groove 20 if` deemed necessary for strength, as shown von the corners 3', Fig. 2, but ordinarily these will not be needed.

From the foregoing it will be seen that I have invented a corner connection which is rigid, economical of metal not so much for the sake of saving themetal as for the sake of avoiding shrinkage distortion, and which fastens the panel, preferably non-metallic, to the metal by integral pluglike portions expanded oppositely to one another, 'hus iirmly wedging the non-metallic panel against movement in any direction.

The opposite flare of the lines of holes causes the ,metal in the holes, as it shrinks in cooling, to pull towards the small ends of the holes. Consequently, since the holes are flared and tapered oppositely to one another, the metal in the holes I4 pulls outwardly, and that in the holes I3 pulls inwardly, resulting in a very rm clamping effect' on the panel, especially resisting inward or outward tendencies. Movement of the panel in its own plane is of course also resisted by the metal in the holes, but also by the metal in the gro'oves I and I2.

The ends of the panels I and 2 are completely covered by metal, and so are fully protected from breakage, and the edges of the grooves are likewise protected either by being completely embedded in metal as with the groove I0 or fully backed up by metal along the edge of the groove, as with the groove I2.

Other modes of applying the principle of my invention may be employed instead of the one explained, change being made as regards the structure herein disclosed, provided the means stated by theA following claim or the equivalent of such stated means be employed.

I therefore particularly point out and distinctly claim as my invention:

A mold container comprising in combination a plurality of metallic corners, and non-metallic Walls connected thereby, said walls having their inner and outer faces exposed except adjacent the ends, and the inner and outer faces of said ends surrounded by the metal of said corners.

JAMES F. HINES. 

